CN116378976A - Centrifugal air compressor - Google Patents

Abstract

The invention provides a centrifugal air compressor, which includes a motor casing and a motor shaft. The two ends of the motor casing are respectively provided with a first end cover and a second end cover. The first end of the motor shaft is rotatably connected to the first On the end cover, the second end of the motor shaft is rotatably connected to the second end cover, the first end of the motor shaft is interference-fitted with a thrust plate, and the side of the first end cover away from the motor casing has a first compression part, the thrust plate includes a sleeve that fits with the motor shaft in an interference fit, and a first cooling channel passing through both ends of the sleeve is constructed inside the sleeve. The airflow in the compression cavity of the first compression part can flow from the first cooling channel to the Flow into one port and flow out of a second port. The invention forms effective and targeted cooling for the thrust plate, reduces the temperature rise of the thrust plate, especially the sleeve, further reduces the thermal deformation of the sleeve, and effectively prevents the interference fit between the thrust plate and the motor shaft due to Separation occurs when heated, which improves the reliability of the air compressor and reduces the accident rate during operation.

Description

Centrifugal air compressor

technical field

The invention belongs to the technical field of compressor design, and in particular relates to a centrifugal air compressor.

Background technique

At present, the design of centrifugal air compressors that use gas bearings as rotor support generally adopts the direct drive of the motor to perform work. The motor rotor and the main shaft are an integrated structure. The shaft end of the main shaft is equipped with a centrifugal impeller, and the impeller is built in the volute outside the motor. . Through the ultra-high-speed rotation of the motor rotor, the high-speed rotation of the impeller is driven to continuously compress the air in the volute, and the high-pressure, high-temperature compressed air is supplied to the fuel cell engine to participate in the electrochemical reaction inside the fuel cell stack, in which the air bearing is the rotor ( Including impeller-thrust disc-main shaft-impeller, taking the two-stage centrifugal air compressor as an example) to provide the necessary support for the high-speed rotation of the integrated rotating parts.

In order to ensure the pressure and flow of the output air, the centrifugal air compressor needs to run in the ultra-high speed region (above 80,000 Rpm) for a long time, and the ultra-high-speed rotor will also cause heat dissipation and cooling problems for the whole machine and the gas bearing. Therefore, when the air compressor works for a long time, a large amount of heat will be generated when the motor stator is energized and the rotor rotates at high speed. The heat accumulated inside the air compressor (mainly in the motor housing) will affect the motor stator and its control circuit. As well as the running state of the rotor and the gas bearing of the motor, heat dissipation must be realized in a timely and effective manner. In the process of long-term high-speed operation, the rotor and supporting air dynamic pressure bearings are often prone to heat accumulation, resulting in thermal damage to the bearings and failure of the whole machine. Based on the aforementioned heat dissipation requirements, the cooling system of the centrifugal air compressor in the prior art Mostly for the cooling of motor rotors, stators and air dynamic pressure bearings, for example, in some related technologies, a part of the compressed air flows through the comb-tooth seal structure between the compressor diffuser and the rotating shaft and is guided into each bearing as cooling gas The location and the inside of the motor realize heat dissipation for related components. The cooling effect of this method is generally deviated due to the relatively small amount of cooling gas. The method of interference fit is often used between them. Due to the lack of necessary special cooling, when the air compressor is running at high speed, there is a difference in the deformation between the thrust plate and the motor shaft after temperature rise, and there is a difference between the thrust plate and the motor shaft. Heat separation phenomenon, when the materials of the two are inconsistent, this phenomenon is more obvious, which reduces the reliability of the air compressor and increases the accident rate of the air compressor operation; in addition, due to the poor heat dissipation performance of the thrust plate, the long-term Running for a long time will cause heat accumulation inside the cavity of the thrust disc, which will induce deformation of the thrust disc and affect reliability.

Contents of the invention

Therefore, the present invention provides a centrifugal air compressor, which can solve the phenomenon that the thrust plate and the motor shaft of the centrifugal air compressor in the prior art are separated due to lack of necessary targeted cooling, resulting in the separation of the two due to heat. The reliability of the press is low, the accident rate is high, and the heat accumulation at the thrust plate causes its deformation to be large, which reduces the technical problems of reliability.

In order to solve the above problems, the present invention provides a centrifugal air compressor, which includes a motor casing and a motor shaft. The two ends of the motor casing are respectively provided with a first end cover and a second end cover. One end is rotatably connected to the first end cover, the second end of the motor shaft is rotatably connected to the second end cover, and the first end of the motor shaft is interference-fitted with a thrust The side of the first end cover away from the motor casing has a first compression part, and the thrust plate includes a sleeve that is interference fit with the motor shaft, and the sleeve is configured with a The air flow in the compression chamber of the first compression part can flow in from the first port of the first cooling flow channel and flow out from the second port.

In some embodiments, there is a first impeller in the compression cavity of the first compression part, the first impeller is connected to the first end, and the first impeller is in the axial direction of the motor shaft. The projection area is a first area, and the first port is located in the first area.

In some embodiments, the sleeve is clamped by the first impeller and a shoulder at the first end of the motor shaft.

In some embodiments, the thrust plate further includes a thrust plate located radially outside of the sleeve, the first compression part further has a first diffuser, and the first diffuser is sleeved on On the third area of the sleeve, the third area is the area between the thrust plate and the first impeller, and the first diffuser and the sleeve pass through the first comb structure seal.

In some embodiments, the motor shaft is rotatably connected to the first end cover through a first radial air dynamic pressure bearing, and the airflow flowing out of the second port can pass through the first radial air dynamic pressure bearing. The pressure bearing enters the cavity of the motor.

In some embodiments, the shaft shoulder is located between the first radial aerodynamic bearing and the thrust plate, and an overflow groove is configured on the shaft end of the shaft shoulder, and the second port and the The overflow slots are provided correspondingly, and the overflow slots can guide the airflow flowing out of the second port outward along the radial direction of the shaft shoulder.

In some embodiments, a second cooling channel is configured in the first end of the motor shaft, and the air flow from the second port can enter the motor cavity through the second cooling channel.

In some embodiments, the side of the second end cover away from the motor casing has a second compression portion, a third cooling channel is configured in the second end of the motor shaft, and the second compression portion The airflow in the compression cavity can enter the motor cavity through the third cooling channel.

In some embodiments, there is a second impeller in the compression cavity of the second compression part, the second impeller is connected to the second end, and the second impeller is in the axial direction of the motor shaft. The projected area is the second area, and the entrance of the third cooling channel is located in the second area.

In some embodiments, the second compression part further has a second diffuser, the second diffuser is sleeved on the second end of the motor shaft, and is located between the second impeller and the first diffuser. Between the two end covers, the second diffuser is sealed with the second end by a second comb structure.

In some embodiments, the motor shaft is rotatably connected to the second end cover through a second radial air dynamic pressure bearing, and the airflow flowing out of the third cooling channel can pass through the second radial The air dynamic pressure bearing enters into the motor cavity; and/or, the outflow port of the third cooling channel is in the motor cavity.

The centrifugal air compressor provided by the present invention can guide the airflow in the compression cavity of the first compression part to the first cooling flow channel constructed in the sleeve, thereby forming effective and targeted cooling for the thrust plate, reducing the The temperature rise of the small thrust plate, especially the sleeve, reduces the amount of thermal deformation (expansion deformation) of the sleeve, effectively prevents the separation phenomenon between the interference fit thrust plate and the motor shaft due to heat, and improves Improve the reliability of the air compressor and reduce the operation accident rate of the air compressor; at the same time, this technical solution optimizes the heat dissipation of the thrust plate, reduces the deformation of the thrust plate due to heat accumulation, and thus improves the operation reliability .

Description of drawings

Fig. 1 is a schematic diagram of the internal structure of a centrifugal air compressor in an embodiment of the present invention (compression part volute and other parts are omitted);

Figure 2 is a partial enlarged schematic view of Figure 1;

Fig. 3 is a schematic structural view (shaft section) of the thrust plate in Fig. 1;

Fig. 4 is the axial projection view of the thrust plate in Fig. 3;

Fig. 5 is a kind of implementation of the overflow groove at the shoulder of the motor shaft in Fig. 1;

Fig. 6 is another implementation of the flow groove at the shoulder of the motor shaft in Fig. 1;

Fig. 7 is a schematic diagram of the internal structure of a centrifugal air compressor in another embodiment of the present invention (compression part volute and other components are omitted).

The reference signs are indicated as:

1. Motor casing; 11. First end cover; 12. Second end cover; 2. Motor shaft; 21. Shaft shoulder; 211. Flow groove; 22. Second cooling channel; 23. Third cooling flow 3. Thrust plate; 31. Sleeve; 32. First cooling channel; 33. Thrust plate; 41. Axial aerodynamic bearing; 42. First radial aerodynamic bearing; 43. The first Two radial air dynamic pressure bearings; 51, the first impeller; 52, the first diffuser; 521, the first comb structure; 61, the second impeller; 62, the second diffuser; 621, the second comb Structure; 7. Motor stator.

Detailed ways

Referring to Fig. 1 to Fig. 7, according to an embodiment of the present invention, a centrifugal air compressor is provided, including a motor casing 1 and a motor shaft 2, the motor casing 1 is a motor chamber, and the motor chamber is provided with The motor shaft 2 and the motor stator 7 on the radially outer side of the motor shaft 2, after the winding in the motor stator 7 is energized, the motor shaft 2 will be driven to rotate under the action of the magnetic force between the motor stator 7 and the motor shaft 2 , it should be noted that the motor shaft 2 of the present invention is also the collective name of the integrated structure of the motor rotor and the shaft. The two ends of the motor casing 1 have a first end cover 11 and a second end cover 12 respectively. The first end is rotatably connected to the first end cover 11, the second end of the motor shaft 2 is rotatably connected to the second end cover 12, the first end of the motor shaft 2 is fitted with a thrust plate 3, The side of the first end cover 11 far away from the motor casing 1 has a first compression part, which is used to compress the air in its compression chamber, and at this time, an axial air dynamic pressure bearing 41 is provided corresponding to the thrust plate 3 , so as to achieve the limitation of the axial position of the motor shaft 2 and prevent the axial movement of the motor shaft 2 during the operation of the air compressor. Referring to Fig. 1, Fig. 7 and Fig. 3, the thrust plate 3 includes the The sleeve 31 of the motor shaft 2 is fitted with interference fit. The sleeve 31 is configured with a first cooling channel 32 passing through its two ends. The airflow in the compression cavity of the first compression part can flow from the first port of the first cooling channel 32. into and out of the second port. In this technical solution, the airflow in the compression cavity of the first compression part can be guided to the first cooling channel 32 constructed in the sleeve 31, so that the thrust plate 3 can be effectively and targetedly cooled, and the thrust plate can be reduced in size. 3, especially the temperature rise at the sleeve 31, thereby reducing the amount of thermal deformation (expansion deformation) of the sleeve 31, effectively preventing the interference-fit thrust plate 3 and the motor shaft 2 from being separated due to heat, and further Improve the reliability of the air compressor and reduce the operation accident rate of the air compressor; at the same time, this technical solution optimizes the heat dissipation of the thrust plate, reduces the deformation of the thrust plate due to heat accumulation, and thus improves the reliability of operation sex. This technical solution is more applicable when the materials of the thrust plate 3 and the motor shaft 2 are different. The aforesaid first end cover 11 or second end cover 12 can be integrated with the motor casing 1 , of course, the three can also be assembled as a whole.

It can be understood that the air flow area of the first cooling flow channel 32 should be limited, on the premise that the driving performance of the first compression part or the motor will not be significantly reduced. In a specific embodiment, through the first cooling flow It is advisable that the flow of air guided by the channel 32 is 2%-3% of the high-pressure air flow in the compression chamber of the first compression part. 31 at uniform intervals in the circumferential direction), when multiple cooling channels 32 are provided, the guided air flow of the aforementioned first cooling channels 32 is the sum of the flow rates of the first cooling channels 32 . The above-mentioned first cooling channel 32 may have various structural types, and for the convenience of its structure, it is preferably linear, that is, a left-right through-type in the orientation shown in FIG. 1 .

In some embodiments, the compression cavity of the first compression part is formed in the first volute (not shown in the figure), and there is a first impeller 51 in the compression cavity, the first impeller 51 is connected to the first end, and the first impeller 51 is connected to the first end. The projection area of an impeller 51 on the axial direction of the motor shaft 2 is the first area, and the first port is in the first area. In the compression chamber, the first area is also the back side of the first impeller 51. The air flow here The pressure is relatively low, and the setting of the first port here can prevent the high-pressure airflow from flowing out of the place too much, which will cause the compression energy efficiency of the first compression part or the motor drive energy efficiency to decrease too much.

The sleeve 31 is clamped by the first impeller 51 and the shoulder 21 of the first end of the motor shaft 2, that is, the thrust plate 3 in this application is in direct contact with the first impeller 51 and formed in the axial direction of the motor shaft 2. positioning, instead of using gaskets in the prior art to compensate for the axial position, so that the axial length of the sleeve 31 in this application is longer and longer than that of the structure with gaskets There is a larger fit area between 31 and the motor shaft 2, which further improves the relative stability of the position between the thrust plate 3 and the motor shaft 2 after the interference fit.

The thrust disc 3 also includes a thrust plate 33 on the radially outer side of the sleeve 31, and the first compression part also has a first diffuser 52, and the first diffuser 52 is sleeved on the third area of the sleeve 31, In the third area, the area between the thrust plate 33 and the first impeller 51, the first diffuser 52 and the sleeve 31 are sealed by the first comb-tooth structure 521, and the first comb-tooth structure 521 can compress the first The gas in the inner part forms a labyrinth seal, preventing too much airflow from entering the motor side through the first through hole, and at the same time allowing a small part of the airflow to enter the motor side together with the aforementioned first cooling channel 32 to form heat generation on the motor side Components such as the motor stator 7, the motor shaft 2 and the heat dissipation of each bearing, the total amount of cooling gas entering the motor side is increased to a certain extent, which is conducive to further improving the overall heat dissipation performance and reliability of the air compressor. It can be understood that, at this time, the cooling airflow passing through the first comb structure 521 will firstly cool the axial air dynamic pressure bearing 41 .

Referring to FIG. 1, the motor shaft 2 is rotatably connected to the first end cover 11 through the first radial air dynamic pressure bearing 42, and the air flow out of the second port can enter the motor through the first radial air dynamic pressure bearing 42. In this way, the cooling airflow in the first cooling channel 32 can cool the first radial air dynamic pressure bearing 42 and then further cool the motor shaft 2 and the motor stator 7 in the motor.

Further referring to Fig. 5 and Fig. 6, the shaft shoulder 21 is located between the first radial aerodynamic pressure bearing 42 and the thrust plate 3, and the shaft end of the shaft shoulder 21 is configured with an overflow groove 211, and the second port is connected to the overflow port. Flow grooves 211 are provided correspondingly, and the flow grooves 211 can guide the airflow flowing out of the second port outward along the radial direction of the shoulder 21. At this time, the inlets of the flow grooves 211 correspond to the outlets of the first cooling channels 32 form a fit, and the outlet of the overflow groove 211 corresponds to the position of the axial air dynamic pressure bearing 41 and the first radial air dynamic pressure bearing 42, that is, the cooling air flow in the first cooling channel 32 can cool the aforementioned two bearings. There are a plurality of overflow grooves 211 arranged at even intervals along the circumferential direction of the shoulder 21. The inlets of each overflow groove 211 are collectively connected through an annular groove, and the annular groove is arranged opposite to the outlet of each first cooling channel 32 to form an air flow. Undertake, so as to form a circumferentially uniform cooling effect. The overflow groove 211 can be a straight groove as shown in FIG. 6 or an arc groove as shown in FIG. 5 .

Referring to FIG. 7 , a second cooling channel 22 is configured in the first end of the motor shaft 2, and the second cooling channel 22 extends along the axial direction of the motor shaft 2, and the air flow from the second port can pass through the second The cooling channel 22 enters the motor cavity, so that the cooling air flow drawn from the first cooling channel 32 can sufficiently and efficiently cool the motor shaft 2, effectively preventing the motor shaft 2 from contacting the first radial air dynamic pressure bearing 42 The accumulation of heat in the corresponding area prevents the heated shaft extension of the motor shaft 2, avoids the thermal bending effect of the motor shaft 2 under high temperature conditions, and improves the service life of the rotor.

Continuing to refer to FIG. 7 , the side of the second end cover 12 away from the motor casing 1 has a second compression part marked in the figure, the second compression part has a second volute not shown in the figure, and the motor shaft 2 A third cooling channel 23 is configured in the second end, and the third cooling channel 23 extends along the axial direction of the motor shaft 2. The compression cavity of the second compression part is formed in the second volute. The air flow in the second volute can pass through the first The three cooling passages 23 enter the motor chamber, that is, the centrifugal air compressor in this technical solution is a two-stage centrifugal air compressor, and the airflow in the compression chamber of the second compression part is guided through the third cooling passage 23 To achieve cooling of the components in the motor cavity, and to form a more comprehensive cooling of the components in the motor cavity at both ends of the axial direction, the effect is better.

There is a second impeller 61 in the compression chamber of the second compression part, and the second impeller 61 is connected to the second end. The projection area of the second impeller 61 on the axial direction of the motor shaft 2 is the second area, and the third cooling channel The inlet of 23 is in the second area. In the compression chamber, the second area is the back side of the second impeller 61. The airflow pressure here is relatively small. Setting the inlet of the third cooling channel 23 here can It is prevented that excessive flow of high-pressure airflow here causes the compression energy efficiency of the second compression part or the motor drive energy efficiency to decrease too much.

The second compression part also has a second diffuser 62, the second diffuser 62 is sleeved on the second end of the motor shaft 2, and is located between the second impeller 61 and the second end cover 12, the second diffuser 62 and the second end are sealed by the second comb-tooth structure 621. On the one hand, the second comb-tooth structure 621 can form a labyrinth seal on the gas in the second compression part, preventing excessive airflow from entering the motor side through the second through hole. At the same time, it can also allow a small part of the airflow to enter the motor side and the aforementioned third cooling channel 23 to jointly form heat dissipation for the heat-generating components on the motor side such as the motor stator 7, the motor shaft 2 and each bearing, and the cooling gas entering the motor side The total amount is further increased, which is conducive to further improving the overall heat dissipation performance and reliability of the air compressor.

The motor shaft 2 is rotatably connected to the second end cover 12 through the second radial air dynamic pressure bearing 43, and the airflow flowing out of the third cooling channel 23 can enter the motor cavity through the second radial air dynamic pressure bearing 43 ( As shown in Figure 1), that is, the outlet of the third cooling channel 23 at this time corresponds to the second radial air dynamic pressure bearing 43, which can further enter the inside of the motor cavity after cooling the bearing first to the motor stator 7 and The motor shaft 2 is further cooled; and/or, the outlet of the third cooling channel 23 is in the motor cavity (as shown in FIG. 7 ), at this time, compared to the design structure of the third cooling channel 23 shown in FIG. 1 , The axial extension length of the third cooling channel 23 in this technical solution is longer, which can form a more sufficient cooling for the motor shaft 2 . However, it can be understood that corresponding outlets are configured on the motor housing 1 so that the airflow flowing out of each cooling flow channel can be discharged out of the motor cavity in time after heat exchange.

Those skilled in the art can easily understand that, on the premise of no conflict, the advantageous technical features of the above-mentioned modes can be freely combined and superimposed.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention. Inside. The above are only preferred embodiments of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the technical principles of the present invention, some improvements and modifications can also be made, and these improvements and modifications should also be It is regarded as the protection scope of the present invention.

Claims (11)

1. A centrifugal air compressor comprises a motor casing (1), a motor shaft (2), and the two ends of the motor casing (1) have a first end cover (11) and a second end cover ( 12), the first end of the motor shaft (2) is rotatably connected to the first end cover (11), and the second end of the motor shaft (2) is rotatably connected to the second On the end cover (12), the first end of the motor shaft (2) is fitted with a thrust disc (3), and the first end cover (11) is away from the side of the motor casing (1) It has a first compression part, and it is characterized in that the thrust plate (3) includes a sleeve (31) that fits with the motor shaft (2) in an interference fit, and the sleeve (31) is configured with a The airflow in the compression chamber of the first compression part can flow in from the first port of the first cooling flow channel (32) and flow out from the second port. 2. The centrifugal air compressor according to claim 1, characterized in that, there is a first impeller (51) in the compression cavity of the first compression part, and the first impeller (51) is connected to the first impeller (51). On one end, the projected area of the first impeller (51) in the axial direction of the motor shaft (2) is a first area, and the first port is located in the first area. 3. The centrifugal air compressor according to claim 2, characterized in that, the sleeve (31) is covered by the first impeller (51) and the shoulder of the first end of the motor shaft (2) (21) Clamping. 4. The centrifugal air compressor according to claim 3, characterized in that, the thrust plate (3) further comprises a thrust plate (33) on the radially outer side of the sleeve (31), so The first compression part also has a first diffuser (52), and the first diffuser (52) is set on the third area of the sleeve (31), and the third area is the end of the sleeve (31). In the area between the push plate (33) and the first impeller (51), the first diffuser (52) and the sleeve (31) are sealed by a first comb structure (521). 5. The centrifugal air compressor according to claim 3, characterized in that, the motor shaft (2) is rotatably connected to the first end cover ( 11), the airflow flowing out of the second port can enter the motor casing (1) through the first radial aerodynamic pressure bearing (42). 6. The centrifugal air compressor according to claim 5, characterized in that, the shaft shoulder (21) is located between the first radial aerodynamic pressure bearing (42) and the thrust plate (3) Between, the shaft end of the shoulder (21) is configured with an overflow groove (211), the second port is set corresponding to the overflow groove (211), and the overflow groove (211) can The airflow flowing out of the second port is directed outward along the radial direction of the shoulder (21). 7. The centrifugal air compressor according to claim 3, characterized in that, a second cooling channel (22) is configured in the first end of the motor shaft (2), and the airflow flowing out of the second port It can enter into the motor cavity through the second cooling channel (22). 8. The centrifugal air compressor according to claim 1 or 7, characterized in that, the side of the second end cover (12) away from the motor casing (1) has a second compression part, the A third cooling channel (23) is configured in the second end of the motor shaft (2), and the airflow in the compression cavity of the second compression part can enter the motor cavity through the third cooling channel (23). 9. The centrifugal air compressor according to claim 8, characterized in that, there is a second impeller (61) in the compression chamber of the second compression part, and the second impeller (61) is connected to the first On both ends, the projection area of the second impeller (61) in the axial direction of the motor shaft (2) is the second area, and the entrance of the third cooling channel (23) is in the second area Inside. 10. The centrifugal air compressor according to claim 9, characterized in that, the second compression part further has a second diffuser (62), and the second diffuser (62) is sleeved on the On the second end of the motor shaft (2), and between the second impeller (61) and the second end cover (12), the second diffuser (62) and the second end Sealed by the second comb structure (621). 11. The centrifugal air compressor according to claim 8, characterized in that, the motor shaft (2) is rotatably connected to the second end cover ( 12), the air flow out of the third cooling channel (23) can enter the motor cavity through the second radial air dynamic pressure bearing (43); and/or, the third cooling channel The outflow port of (23) is in the motor cavity.

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